The use of discrete electrical components in modern day electronic devices remains an issue in many fields despite the advances in microelectonics and integrated circuit design. The necessity to provide discrete components may be driven by a number of factors. One such factor may be based on component electrical value while physical size considerations may also be of significance.
In the instance that a customer wishes to manufacture an electrical or electronic system or device requiring the use of capacitor components, such components may take on various roles and, consequently, may require widely varying physical and electrical properties. In some instances, large value capacitors with respect to either capacitive values and/or voltage handling capabilities may be of such physical size as to prohibit direct incorporation of the component into an electronic device. Such may especially be true in the instance of microelectronic or integrated circuit devices.
In other instances, while a particular subject capacitive component may be manufactured so as to be of a physical size sufficiently small to be incorporated into smaller electronic devices (including the aforementioned microelectronic and integrated circuit devices), there may be additional impediments to such incorporation. For example, one such reason may involve the need to vary the electrical values of the component in relation to the device or operating conditions with which or under which the component is employed.
High density mounting of electronic components on circuit boards is common in the electronics industry. Miniature ceramic capacitors having multiple layers have been used for some time in electronic devices such as cellular telephones, network routers, computers, and the like. The manufacturing techniques of such devices must be precise to provide for the greatly reduced size of such devices, while still affording desirable electrical operating characteristics.
Various United States patents are directed to aspects of electronic component manufacturing. See, for example, U.S. Pat. No. 6,577,491 to Ohtsuka et al.; U.S. Pat. No. 6,515,842 to Hayworth, et al.; U.S. Pat. No. 6,243,253 and U.S. Pat. No. 5,880,925 to DuPre et al.; U.S. Pat. No. 5,590,016 to Fujishiro et al.; U.S. Pat. No. 5,565,838 to Chan; U.S. Pat. No. 5,548,474 to Chen at al.; U.S. Pat. No. 5,367,430 to DeVoe et al.; U.S. Pat. No. 5,159,300 to Nakamura et al.; U.S. Pat. No. 4,947,286 to Kaneko et al.; U.S. Pat. No. 4,574,438 to Diepers, et al.; U.S. Pat. No. 3,635,759 to Howatt; U.S. Pat. No. 3,617,834 to Rayburn; U.S. Pat. No. 3,538,571 to Callahan et al.; and U.S. Pat. No. 3,117,365 to Belko, Jr. The above referenced patents are for all purposes hereby incorporated by reference into this disclosure as if fully set forth herein.
For some time, the design of various electronic components has been driven by a general industry trend toward miniaturization. In such regard, a need generally exists for smaller electronic components having exceptional operating characteristics. For example, some applications require a large capacitance value, but are severely limited in the amount of space (often referenced as “real estate”) such a capacitor may occupy on a circuit board.
Multi-layer ceramic devices, sometimes referred to as “multi-layer ceramic capacitors” or “MLCC's,” are often constructed with a plurality of alternating ceramic and electrode layers arranged in a stack. During manufacture, such layers may be pressed and formed into a vertically stacked structure. Such MLCC's may have a single capacitor on a chip, or may include several capacitors in an array. However, such capacitors typically have one pre-set capacitance value that cannot later be altered.
With the desire to increase functionality and reduce the size of such components, manufacturers are looking for new ways to provide varying (i.e., multiple) capacitance values in microcircuits. However, as the size of capacitors decreases, the dead space or spacing that must exist between capacitors when mounted on a circuit board becomes relatively more important as a limiting factor in miniaturizing a design.
More recently, manufacturers have sought ways to reduce the size of capacitor arrays while simultaneously also increasing the flexibility of such capacitor arrays. In the context of the present disclosure, the term capacitor array is meant to describe a unit comprised of multiple capacitors. A significant limitation of current designs is that many currently known arrayed capacitors, once installed and constructed in the chip, are not variable as to its value (i.e., the degree to which it can hold a charge).
A capacitor array having capacitors of various values within a single chip would be highly desirable. Thus, a capacitor array design providing board manufacturers and assemblers more flexibility by affording multiple capacitance values on a single chip would be desirable.
While various implementations of multiple capacitance devices and capacitor array devices have been developed, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.